Picoblaze-3 differences compared to Picoblaze-1

[dwerdna]

Hi all

Just wondering if there are any known issues in porting code written
for a Picoblaze-1/Spartan-2 into a Picoblaze-3/Spartan-3?? Obviously
there are a couple of new instructions and more code space that I can
take advantage off, but any modifications to the legacy instruction
set??

Thanks

Andrew